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Biomedical subjects

Richard M Martin

Publications and source records attributed to Richard M Martin.

At least 19 recordsLinked to original sources
PubMed2007

Statins and risk of cancer: a systematic review and metaanalysis.

We conducted a systematic review of the association between HMG-CoA reductase inhibitor (statin) use and cancer risk. We searched MEDLINE, EMBASE, Web of Science, ISI Proceedings and BIOSIS Previews bibliographic databases, electronic trials registers and reference lists for potentially eligible randomized trials and observational studies. Thirty-eight individual studies (26 randomized trials involving 103,573 participants and 12 observational studies with 826,854 participants) were included. Median follow-up was 3.6 and 6.2 years for trials and observational studies, respectively. In metaanalyses of randomized trials, there was no evidence that statin therapy was associated with incidence of all-cancers (26 trials; pooled risk ratio = 1.00; 95% CI 0.95-1.05; I(2) = 0%) or the following site-specific cancers: breast (7 trials; risk ratio = 1.01; 0.79-1.30; I(2) = 43%), prostate (4 trials; risk ratio = 1.00; 0.85-1.17; I(2) = 0%), colorectum (9 trials; risk ratio = 1.02; 0.89-1.16; I(2) = 0%), lung (9 trials; risk ratio = 0.96; 0.84-1.09; I(2) = 0%), genito-urinary (5 trials; risk ratio = 0.95; 0.83-1.09; I(2) = 0%), melanoma (4 trials; risk ratio = 0.86; 0.62-1.20; I(2) = 17%) or gastric (1 trial; risk ratio = 1.00; 0.35-2.85). There was no evidence of differential effects by length of follow-up, statin type (lipophilic vs. lipophobic) or potency. Trial results were generally consistent with observational studies. We conclude that statin use is not associated with short-term cancer risk, but longer-latency effects remain possible.

Humans↗
PubMed2006

Finite-size error in many-body simulations with long-range interactions.

We discuss the origin of the finite-size error of the energy in many-body simulation of systems of charged particles and we propose a correction based on the random-phase approximation at long wavelengths. The correction is determined mainly by the collective charge oscillations of the interacting system. Finite-size corrections, both on kinetic and potential energy, can be calculated within a single simulation. Results are presented for the electron gas and silicon.

Journal Article↗
PubMed2006

Associations of adiposity from childhood into adulthood with insulin resistance and the insulin-like growth factor system: 65-year follow-up of the Boyd Orr Cohort.

CONTEXT: One metabolic pathway through which adiposity influences disease risk may be via alterations in insulin and IGF metabolism. OBJECTIVE: Our objective was to investigate associations of adiposity at different stages of life with insulin and the IGF system. DESIGN, SETTING, AND PARTICIPANTS: The study was a 65-yr follow-up of 728 Boyd Orr cohort participants (mean age, 71 yr) originally surveyed between 1937 and 1939. MAIN OUTCOMES: Outcomes included homeostasis model assessment of insulin resistance, total IGF-I and IGF-II, IGF binding protein (IGFBP)-2, and IGFBP-3 in adulthood. RESULTS: Childhood body mass index (BMI) was weakly inversely related to adult IGF-I (coefficient per BMI sd, -3.4 ng/ml; 95% confidence interval, -7.3 to 0.5; P = 0.09). IGF-II (but not IGF-I) increased with higher current fat mass index (coefficient, 26.1 ng/ml; 95% confidence interval, 4.6 to 47.6; P = 0.02) and waist-hip ratio (30.0 ng/ml; 9.4 to 50.5; P = 0.004). IGFBP-2 decreased by 21.2% (17.2 to 24.9; P < 0.001), and homeostasis model assessment of insulin resistance increased by 38.8% (28.9 to 49.6; P < 0.001) per sd higher adult BMI. Among thin adults (BMI tertiles 1 and 2), IGFBP-2 was positively, and insulin resistance was inversely, associated with childhood BMI. CONCLUSION: There was only weak evidence that associations of childhood BMI with chronic disease risk may be mediated by adult IGF-I levels. Circulating IGFBP-2 in adulthood, a marker for insulin sensitivity, was inversely associated with current adiposity, but overweight children who became relatively lean adults were more insulin sensitive than thinner children. The findings may indicate programming of later insulin sensitivity and consequently IGFBP-2 levels in response to childhood adiposity. The role of IGF-II in obesity-related chronic diseases warrants additional investigation.

Adiposity↗
PubMed2006

Oxycodone for cancer-related pain: meta-analysis of randomized controlled trials.

To evaluate the efficacy and tolerability of oxycodone in cancer-related pain, we conducted a systematic review of randomized controlled trials. Four studies, comparing oral oxycodone with either oral morphine (n = 3) or oral hydromorphone (n = 1), were suitable for meta-analysis. Standardized mean differences in pain scores comparing oxycodone with control groups were pooled using random-effects models. Overall, there was no evidence that mean pain scores differed between oxycodone and control drugs (pooled standardized mean difference, 0.04; 95% confidence interval [CI], -0.29 to 0.36; P = .8; I(2) = 62%). In meta-regression analyses, pain scores were higher for oxycodone compared with morphine (0.20; 95% CI, -0.04 to 0.44) and lower compared with hydromorphone (-0.36; 95% CI, -0.71 to 0.00), although these effect sizes were small. The efficacy and tolerability of oxycodone are similar to morphine, supporting its use as an opioid for cancer-related pain.

Analgesics, Opioid↗
PubMed2006

Quantum Monte Carlo method using a stochastic Poisson solver.

The quantum Monte Carlo (QMC) technique is an extremely powerful method to treat many-body systems. Usually the quantum Monte Carlo method has been applied in cases where the interaction potential has a simple analytic form, like the 1/r Coulomb potential. However, in a complicated environment as in a semiconductor heterostructure, the evaluation of the interaction itself becomes a nontrivial problem. Obtaining the potential from any grid-based finite-difference method for every walker and every step is infeasible. We demonstrate an alternative approach of solving the Poisson equation by a classical Monte Carlo calculation within the overall quantum Monte Carlo scheme. We have developed a modified "walk on spheres" algorithm using Green's function techniques, which can efficiently account for the interaction energy of walker configurations, typical of quantum Monte Carlo algorithms. This stochastically obtained potential can be easily incorporated with variational, diffusion, and other Monte Carlo techniques. We demonstrate the validity of this method by studying a simple problem, the polarization of a helium atom in the electric field of an infinite capacitor.

Journal Article↗
PubMed2006

Associations of childhood and adulthood height and the components of height with insulin-like growth factor levels in adulthood: a 65-year follow-up of the Boyd Orr cohort.

CONTEXT: Taller individuals with longer legs have a higher risk of cancer but a lower risk of coronary heart disease. OBJECTIVE: We investigated whether childhood height and its components are associated with the IGF system in adulthood. DESIGN AND PARTICIPANTS: We analyzed data from 429 participants of the Boyd Orr cohort, for whom height measured in childhood (mean age, 7.4 yr) in 1937-1939 could be related to levels of IGF-I, IGF-II, IGF binding protein (IGFBP)-2, and IGFBP-3 in adulthood (mean age, 71.1 yr). In 385 participants, measured height in adulthood could be related to IGF levels. RESULTS: In fully adjusted models (controlling for age, sex, socioeconomic factors, lifestyle, and body mass index), childhood height and its components were not associated with adult circulating IGF-I, IGF-II, or IGFBP-2 levels. IGFBP-3 was 85.5 ng/ml higher (95% confidence interval, -11.6 to 182.5; P = 0.08) per sd increase in childhood trunk length and 83.6 ng/ml lower (95% confidence interval, -10.3 to 177.5; P = 0.08) per sd increase in childhood leg/trunk ratio. Height in adulthood was not associated with IGF-I, IGF-II, or IGFBP-3 and was inversely associated with IGFBP-2 (P = 0.05) after additionally controlling for childhood height. CONCLUSION: There was no evidence that associations of childhood height with cancer and coronary heart disease risk are mediated by IGF-I in adulthood. The anthropometric associations with IGFBP-2 and IGFBP-3 could be chance findings but warrant additional investigation. IGF levels in childhood may be more important determinants of long-term disease risk than adult levels.

Adolescent↗
PubMed2006

Continuing controversy over monitoring men with localized prostate cancer: a systematic review of programs in the prostate specific antigen era.

PURPOSE: There is continuing controversy over the most appropriate treatment for screen detected and clinically localized prostate cancer, and increasing interest in monitoring such men initially with radical treatment targeted at cancers showing signs of progressive potential but while they are still curable. Current evidence on monitoring protocols and biomarkers used to predict disease progression was systematically reviewed. MATERIALS AND METHODS: The MEDLINE and Excerpta Medica (EMBASE) bibliographic databases were searched from 1988 to October 2004, supplemented by manual searches of reference lists, focusing on studies reporting monitoring of men with localized prostate cancer. RESULTS: A total of 48 potentially eligible articles were found but only 5 studies, in which there was a total of 451 participants, restricted entry criteria to men with clinically localized (T1-T2) prostate cancer. Monitoring protocols varied with little consensus, although the majority used prostate specific antigen and digital rectal examination, while some added re-biopsy to assess progression. Actuarial probabilities of freedom from disease progression at 4 to 5 years of followup were 67% to 72%. However, up to 50% of men abandoned monitoring within 2 years, largely because of anxiety related to increasing prostate specific antigen rather than objective evidence of disease progression. There was no robust evidence to support prostate specific antigen doubling times or velocity to identify men in whom disease may progress. Studies were characterized by small sample size, short-term followup, observer bias and uncertain validity around variable definitions of progression. CONCLUSIONS: Current evidence suggests that some form of monitoring would be a suitable treatment option in men with localized prostate cancer but there is little consensus over what markers should be used in such a program or how progression should be properly defined. The search for a method that safely identifies men with prostate cancer who could avoid radical intervention must continue.

Disease Progression↗
PubMed2006

Association of body mass index measured in childhood, adolescence, and young adulthood with risk of ischemic heart disease and stroke: findings from 3 historical cohort studies.

BACKGROUND: It is unclear whether early life body mass index (BMI; in kg/m(2)) is associated with adult cardiovascular disease. OBJECTIVE: The objective was to assess the association of early life BMI with the risk of ischemic heart disease (IHD) and stroke. DESIGN: The association between early life BMI and risk of adult mortality from IHD and stroke was assessed in 3 historical cohort studies in which height and weight had been assessed by using standard procedures. Participants were traced and linked to national mortality data. Participants in the 3 cohorts were born between 1922 and 1937, 1927 and 1956, and 1928 and 1950 and were aged 2-15, 9-18, and 16-22 y, respectively, at the time of assessment of their height and weight. RESULTS: Participants in all 3 cohorts had mean BMIs similar to those reported for contemporary children and young adults, but fewer of the cohort participants were overweight or obese. BMI was not associated with future risk of IHD or stroke in any cohort. The pooled (all 3 cohorts) adjusted hazard ratio per SD of early life BMI was 1.09 (95% CI: 1.01, 1.19) for IHD and 0.94 (95% CI: 0.82, 1.08) for stroke. The pooled hazard ratio of IHD when participants who were overweight or obese for their age were compared with all other participants was 1.34 (95% CI: 0.95, 1.91), and no association was found between overweight or obesity and stroke risk. The effects of BMI did not vary by cohort or by age. CONCLUSION: These results do not provide strong evidence that being overweight or obese in childhood is associated with future cardiovascular disease risk.

Adolescent↗
PubMed2006

Does breastfeeding influence risk of type 2 diabetes in later life? A quantitative analysis of published evidence.

BACKGROUND: Observational evidence suggests that having been breastfed in infancy may reduce the prevalence of type 2 diabetes in later life. OBJECTIVE: The objective was to examine the influence of initial breastfeeding on type 2 diabetes and blood glucose and insulin concentrations. DESIGN: A systematic review of published studies identified 1010 reports; 23 examined the relation between infant feeding and type 2 diabetes in later life or risk factors for diabetes. Risk factors in infants were examined separately from those in children and adults. All estimates were pooled by using fixed-effect models; differences <0 and ratios <1 imply a beneficial effect of breastfeeding. RESULTS: Subjects who were breastfed had a lower risk of type 2 diabetes in later life than did those who were formula fed (7 studies; 76 744 subjects; odds ratio: 0.61; 95% CI: 0.44, 0.85; P = 0.003). Children and adults without diabetes who had been breastfed had marginally lower fasting insulin concentrations than did those who were formula fed (6 studies; 4800 subjects; percentage difference: -3%; 95% CI: -8%, 1%; P = 0.13); no significant difference in fasting glucose concentrations was observed. Breastfed infants had lower mean preprandial blood glucose (12 studies; 560 subjects; mean difference: -0.17 mmol/L; 95% CI: -0.28, -0.05 mmol/L; P = 0.005) and insulin (7 studies; 291 subjects; mean difference: -2.86 pmol/L; 95% CI: -5.76, 0.04 pmol/L; P = 0.054) concentrations than did those who were formula fed. CONCLUSION: Breastfeeding in infancy is associated with a reduced risk of type 2 diabetes, with marginally lower insulin concentrations in later life, and with lower blood glucose and serum insulin concentrations in infancy.

Adolescent↗
PubMed2006

Did intense adverse media publicity impact on prescribing of paroxetine and the notification of suspected adverse drug reactions? Analysis of routine databases, 2001-2004.

AIM: To document the impact on clinical practice in England of media attention around possible adverse effects of paroxetine. DESIGN: Analysis of national selective serotonin reuptake inhibitor (SSRI) prescribing trends and yellow-card adverse drug reaction reports, 2001-2004. RESULTS: From a steady state in 2001, paroxetine prescribing declined sharply from April 2002, coinciding with a USA regulatory action; the subsequent decline in paroxetine prescribing was 1.87% per month (95% confidence interval - 2.06, -1.68). Other SSRI prescribing increased by 1% per month until a major UK review of SSRIs in children in December 2003, after which prescribing plateaued. Media publicity was associated with short-term peaks in yellow-card reports related to paroxetine. CONCLUSION: Falls in paroxetine and other SSRI prescribing in the UK coincided, respectively, with regulatory communications from the USA and the UK, but associations may have noncausal or other explanations. Reports of adverse reactions to paroxetine appeared to increase after adverse media publicity about the drug.

Adverse Drug Reaction Reporting Systems↗
PubMed2005

Breast-feeding and childhood cancer: A systematic review with metaanalysis.

It has been suggested that breast milk may play a role in the prevention of certain childhood cancers. We undertook a systematic review of published studies investigating the association between breast-feeding and childhood cancers using Medline (1966 to June 2004), supplemented with auto alerts and manual searches. Analyses are based on odds ratios for specific cancers among those ever breast-fed compared with those never breast-fed, pooled using random-effects models. Forty-nine publications were potentially relevant; of these, 26 provided odds ratio estimates for at least one childhood cancer outcome and were included in metaanalyses. Overall, 92% of the studies were case-control studies, 85% relied on long-term recall of feeding history, only 8% examined breast-feeding exclusivity and control response rates were under 80% in over half. Metaanalyses suggested lower risks associated with having been breast-fed of 9% (95% CI = 2-16%) for acute lymphoblastic leukemia, 24% (3-40%) for Hodgkin's disease and 41% (22-56%) for neuroblastoma, with little between-study heterogeneity. The estimates for Hodgkin's disease and neuroblastoma, however, were driven by single studies. There was little evidence that breast-feeding was associated with acute nonlymphoblastic leukemia, non-Hodgkin's lymphoma, central nervous system cancers, malignant germ cell tumors, juvenile bone tumors, or other solid cancers. In conclusion, ever having been breast-fed is inversely associated with acute lymphoblastic leukemia, Hodgkin's disease and neuroblastoma in childhood, but noncausal explanations are possible. Even if causal, the public health importance of these associations may be small. Our estimates suggest that increasing breast-feeding from 50% to 100% would prevent at most 5% of cases of childhood acute leukemia or lymphoma. (c) 2005 Wiley-Liss, Inc.

Adolescent↗
PubMed2005

Breast-feeding and cancer: the Boyd Orr cohort and a systematic review with meta-analysis.

BACKGROUND: Having been breast-fed has been suggested to influence cancer risk in adulthood. We investigated associations between breast-feeding during infancy and adult cancer incidence and mortality in a cohort study and meta-analyses of published studies. METHODS: The Boyd Orr cohort consisted of 4999 subjects who were originally surveyed in 1937-39, when they were 0-19 years of age. Cancer outcomes from 1948 through 2003 were available for 4379 (88%) subjects, and 3844 had complete data on all covariates. Associations of breast-feeding with cancer were investigated using proportional hazards models. We also identified 14 studies on infant feeding and cancer published from 1966 through July 2005, of which 10 could be combined with the Boyd Orr cohort results in a meta-analysis of breast cancer using random-effect models. RESULTS: In the Boyd Orr cohort, ever having been breast-fed, compared with never having been breast-fed, was not associated with the incidence of all cancers (hazard ratio [HR] = 1.07, 95% confidence interval [CI] = 0.89 to 1.28) or of any individual cancer type examined (prostate HR = 1.43, 95% CI = 0.58 to 3.52; breast HR = 1.62, 95% CI = 0.89 to 2.94; colorectal HR = 0.86, 95% CI = 0.45 to 1.63; gastric HR = 1.22, 95% CI = 0.47 to 3.15). In the meta-analysis, there was also no association between breast-feeding and breast cancer (regardless of menopausal status) (relative risk [RR] = 0.94, 95% CI = 0.85 to 1.04). However, breast-fed women had a reduced risk of premenopausal breast cancer (RR = 0.88, 95% CI = 0.79 to 0.98) but not of postmenopausal breast cancer (RR = 1.00, 95% CI = 0.86 to 1.16). CONCLUSION: Ever having been breast-fed was not associated with overall breast cancer risk, although the meta-analysis revealed a reduced risk of premenopausal breast cancer in women who had been breast-fed.

Adult↗
PubMed2005

Breastfeeding and atherosclerosis: intima-media thickness and plaques at 65-year follow-up of the Boyd Orr cohort.

OBJECTIVES: The impact of breastfeeding in infancy on cardiovascular disease risk is uncertain. We related breastfeeding in infancy to atherosclerosis in adulthood. METHODS AND RESULTS: A historic cohort study based on a 65-year follow-up of the Carnegie (Boyd Orr) survey of diet and health in prewar Britain, 1937 to 1939. A total of 732 eligible cohort members living in or around Aberdeen, Bristol, Dundee, Wisbech, and London were invited for follow-up examinations in 2002, and 405 (55%) participated. In models controlling for age and sex, breastfeeding was inversely associated with common carotid intima-media thickness (IMT; difference -0.03 mm; 95% CI, -0.07 to 0.01), bifurcation IMT (difference -0.19 mm; 95% CI, -0.37 to -0.01), carotid plaque (odds ratio [OR], 0.52; 95% CI, 0.29 to 0.92), and femoral plaque (OR, 0.54; 95% CI, 0.26 to 1.12), compared with bottle-feeding. Controlling for socioeconomic variables in childhood and adulthood, smoking and alcohol made little difference to effect estimates. Controlling for factors potentially on the causal pathway (blood pressure, adiposity, cholesterol, insulin resistance, and C-reactive protein) made little difference to observed associations. CONCLUSIONS: Breastfeeding may be associated with a reduced risk of atherosclerosis in later life. Measurement error and power considerations limit the extent to which conclusions about the mechanisms underlying this relationship can be made.

Aged↗
PubMed2005

Breastfeeding in infancy and blood pressure in later life: systematic review and meta-analysis.

The influence of breastfeeding on blood pressure in later life is uncertain. The authors conducted a systematic review of published studies from which estimates of a mean difference (standard error) in blood pressure between breastfed and bottle-fed subjects could be derived. They searched MEDLINE and Excerpta Medica (EMBASE) bibliographic databases, which was supplemented by manual searches of reference lists. Fifteen studies (17 observations) including 17,503 subjects were summarized. Systolic blood pressure was lower in breastfed compared with bottle-fed infants (pooled difference: -1.4 mmHg, 95% confidence interval (CI): -2.2, -0.6), but evidence of heterogeneity between study estimates was evident (chi(2)(16) = 42.0, p < 0.001). A lesser effect of breastfeeding on systolic blood pressure was observed in larger (n > or = 1,000) studies (-0.6 mmHg, 95% CI: -1.2, 0.02) compared with smaller (n < 1,000) studies (-2.3 mmHg, 95% CI: -3.7, -0.9) (p for difference in pooled estimates = 0.02). A small reduction in diastolic blood pressure was associated with breastfeeding (pooled difference: -0.5 mmHg, 95% CI: -0.9, -0.04), which was independent of study size. If causal, the small reduction in blood pressure associated with breastfeeding could confer important benefits on cardiovascular health at a population level. Understanding the mechanism underlying this association may provide insights into pathways linking early life exposures with health in adulthood.

Adolescent↗
PubMed2005

The effect of breastfeeding on mean body mass index throughout life: a quantitative review of published and unpublished observational evidence.

BACKGROUND: Evidence from observational studies has suggested that breastfeeding may reduce the prevalence of obesity in later life. OBJECTIVE: The objective was to examine whether initial breastfeeding is related to lower mean body mass index (BMI; in kg/m(2)) throughout life. DESIGN: The study was a systematic review of published studies investigating the association between infant feeding and a measure of obesity or adiposity in later life, which was supplemented with data from unpublished sources. Analyses were based on the mean differences in BMI between those subjects who were initially breastfed and those who were formula-fed (expressed as breastfed minus bottle-fed), which were pooled by using fixed-effects models throughout. RESULTS: From 70 eligible studies, 36 mean differences in BMI (from 355 301 subjects) between those breastfed and those formula-fed (reported as exclusive feeding in 20 studies) were obtained. Breastfeeding was associated with a slightly lower mean BMI than was formula feeding (-0.04; 95% CI: -0.05, -0.02). The mean difference in BMIs appeared larger in 15 small studies of <1000 subjects (-0.19; 95% CI: -0.31, -0.08) and smaller in larger studies of >or=1000 subjects (-0.03; 95% CI: -0.05, -0.02). An Egger test was statistically significant (P = 0.002). Adjustment for socioeconomic status, maternal smoking in pregnancy, and maternal BMI in 11 studies abolished the effect (-0.10; 95% CI: -0.14, -0.06 before adjustment; -0.01; 95% CI: -0.05, 0.03 after adjustment). CONCLUSIONS: Mean BMI is lower among breastfed subjects. However, the difference is small and is likely to be strongly influenced by publication bias and confounding factors. Promotion of breastfeeding, although important for other reasons, is not likely to reduce mean BMI.

Adult↗
PubMed2005

Could associations between breastfeeding and insulin-like growth factors underlie associations of breastfeeding with adult chronic disease? The Avon Longitudinal Study of Parents and Children.

OBJECTIVE: The influence of infant feeding method (breast/formula) on growth factor levels could underlie associations of breastfeeding with childhood growth and risk factors for cardiovascular disease. We investigated associations of having been breastfed with serum IGF-I and IGFBP-3 in childhood. METHODS: Prospective birth cohort study (subsample of the Avon Longitudinal Study of Parents and Children, UK) based on 871 children born in 1991/1992 who underwent clinical follow-up and blood tests at age 7-8 years. A total of 488 (56%) children had complete data. RESULTS: In children with complete data, the age- and sex-standardized IGF-I levels of those who were partially or exclusively breastfed were 6.1 and 13.8 ng/ml higher, respectively, than those who were never breastfed (increase in IGF-I levels per category of breastfeeding exclusivity: 7.1 ng/ml; 95% CI: 0.3-13.9; P = 0.04). In models also controlling for birthweight, gestational age, mother's age, and socioeconomic and dietary factors, the breastfeeding-IGF-I association was attenuated (regression coefficient: 3.3 ng/ml; -4.2-10.7; P = 0.4); further adjustment for IGFBP-3 made little difference (regression coefficient: 4.1 ng/ml; -2.8-10.9; P = 0.2). There was little evidence for an association between breastfeeding and IGFBP-3 or the molar ratio IGF-I/IGFBP-3. CONCLUSIONS: The positive association between breastfeeding and IGF-I could be due to residual confounding or to chance. Nevertheless, the magnitude of the fully adjusted effect estimate and the novelty of the association suggest that larger studies should now be conducted to confirm or refute the hypothesis that variations in IGF-I by infant feeding mode explain associations of breastfeeding with health in later life.

Breast Feeding↗